[11] RFR (XS): JDK-8198293: AARCH64 - Add CPU detection code for Cavium Thunder X2

[Dmitry Samersoff]

Dmitry,

Thank you for the explanation.

The fix looks good to me.

-Dmitry

On 02/20/2018 02:27 PM, Dmitry Chuyko wrote:
> Dmitry,
> 
> Depending on firmware version T99 may be seen as Broadcom 0x516 or as
> Cavium 0xAF. So I'd prefer to leave per-model detection code blocks.
> Nothing common is expected here for T88 and T88.
> 
> -Dmitry C
> 
> 
> On 02/20/2018 10:54 AM, Dmitry Samersoff wrote:
>> Dmitry,
>>
>> I would prefer to have this code better readable/maintainable ever at
>> the cost of some extra lines.
>>
>> i.e.
>>
>> if (_cpu == CPU_CAVIUM) {
>>    if (_model == CAVIUM_THUNDER_X) //0xA1 {
>>        ...
>>    }
>>    if (_model == CAVIUM_THUNDER_X2) //0xAF {
>>      ...
>>    }
>> }
>> else if (_cpu == CPU_BROADCOM ) {
>>     if (_model == 0x516) {
>>         ...
>>     }
>> }
>>
>> -Dmitry
>>
>>
>> On 19.02.2018 17:22, Dmitry Chuyko wrote:
>>> I also made webrev for convenience.
>>>
>>> webrev: http://cr.openjdk.java.net/~dchuyko/8198293/webrev.00/
>>> rfe: https://bugs.openjdk.java.net/browse/JDK-8198293
>>>
>>> -Dmitry
>>>
>>> On 02/16/2018 07:37 PM, Dmitry Chuyko wrote:
>>>> rfe link corrected: https://bugs.openjdk.java.net/browse/JDK-8198293
>>>>
>>>> On 02/16/2018 07:35 PM, Dmitry Chuyko wrote:
>>>>> Hello,
>>>>>
>>>>> Please review a small change in vendor specific features for Cavium
>>>>> CPUs.
>>>>>
>>>>> T88 should be determined more accurate with its model number.
>>>>> T99 may have 2 vendor-model combinations.
>>>>>
>>>>> Flag values for T99 are raw first approximation, I've created a
>>>>> separate sub-task to check them more precisely.
>>>>>
>>>>> rfe: https://bugs.openjdk.java.net/browse/JDK-8198293
>>>>> patch: below
>>>>>
>>>>> -Dmitry
>>>>>
>>>>> diff -r 82d9d5744e5f src/hotspot/cpu/aarch64/vm_version_aarch64.cpp
>>>>> --- a/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp    Fri Feb 16
>>>>> 12:18:09 2018 +0100
>>>>> +++ b/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp    Fri Feb 16
>>>>> 19:15:44 2018 +0300
>>>>> @@ -193,7 +193,9 @@
>>>>>     }
>>>>>       // Enable vendor specific features
>>>>> -  if (_cpu == CPU_CAVIUM) {
>>>>> +
>>>>> +  // ThunderX
>>>>> +  if (_cpu == CPU_CAVIUM && (_model == 0xA1)) {
>>>>>       if (_variant == 0) _features |= CPU_DMB_ATOMICS;
>>>>>       if (FLAG_IS_DEFAULT(AvoidUnalignedAccesses)) {
>>>>>         FLAG_SET_DEFAULT(AvoidUnalignedAccesses, true);
>>>>> @@ -202,6 +204,20 @@
>>>>>         FLAG_SET_DEFAULT(UseSIMDForMemoryOps, (_variant > 0));
>>>>>       }
>>>>>     }
>>>>> +  // ThunderX2
>>>>> +  if ((_cpu == CPU_CAVIUM && (_model == 0xAF)) ||
>>>>> +      (_cpu == CPU_BROADCOM && (_model == 0x516))) {
>>>>> +    if (FLAG_IS_DEFAULT(AvoidUnalignedAccesses)) {
>>>>> +      FLAG_SET_DEFAULT(AvoidUnalignedAccesses, true);
>>>>> +    }
>>>>> +    if (FLAG_IS_DEFAULT(UseSIMDForMemoryOps)) {
>>>>> +      FLAG_SET_DEFAULT(UseSIMDForMemoryOps, true);
>>>>> +    }
>>>>> +    if (FLAG_IS_DEFAULT(UseFPUForSpilling)) {
>>>>> +      FLAG_SET_DEFAULT(UseFPUForSpilling, true);
>>>>> +    }
>>>>> +  }
>>>>> +
>>>>>     if (_cpu == CPU_ARM && (_model == 0xd03 || _model2 == 0xd03))
>>>>> _features |= CPU_A53MAC;
>>>>>     if (_cpu == CPU_ARM && (_model == 0xd07 || _model2 == 0xd07))
>>>>> _features |= CPU_STXR_PREFETCH;
>>>>>     // If an olde style /proc/cpuinfo (cpu_lines == 1) then if _model
>>>>> is an A57 (0xd07)
>>>>>
>>
>